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Transposon-induced pigment-deficient mutants of Porphyromonas gingivalis

Charles I. Hoover, Fuminobu Yoshimura
DOI: http://dx.doi.org/10.1111/j.1574-6968.1994.tb07259.x 43-48 First published online: 1 November 1994


Trypsin-like protease activity, hemagglutination activity, and accumulation of heme-containing compounds (black pigment) are considered to be virulence factors of Porphyromonas gingivalis. Transposon-mutagenesis was used for the first time to isolate pigment-deficient mutants. These mutants exhibited simultaneous deficiency in trypsin-like protease activity and hemagglutination activity. Two major membrane-associated proteins, observed by SDS-PAGE with the parent strain, were essentially absent from the mutant strains. Immunoblot analysis indicated that these two proteins correspond to putative hemagglutinin and hemagglutinin/protease products of P. gingivalis. Each mutant contained only one transposon insertion, thus the pleiotropic phenotype resulted from single site-specific mutations. The results indicate that trypsin-like protease activity is required for accumulation of protoheme from hemoglobin by P. gingivalis and that genetic and/or physiological linkage exists between trypsin-like protease activity and hemagglutination activity.

Key words
  • Porphyromonas gingivalis
  • Transposon mutagenesis
  • Bacterial pigmentation
  • Trypsin-like protease
  • Hemagglutination

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